Detection and molecular characterization of phytoplasmas associated with stone fruit trees in northwest of Iran

Abstract During surveys conducted from 2015 to 2018 in stone fruit orchards of East Azerbaijan province in the northwest of Iran, several stone fruit trees showing phytoplasma typical symptoms such as witches'-broom, little leaf, leaf rolling, leaf scorching, dieback, decline, yellowing, reddening and rosette were sampled. PCR and nested PCR analyses using phytoplasma universal primers confirmed the phytoplasma infection in some of symptomatic almond, peach, plum and sweet cherry trees. Sequence analyses of some 485 bp and 1239 bp 16S–23S rDNA fragments amplified in nested PCR, confirmed that ʻCandidatus Phytoplasma asterisʼ, ʻCa. Phytoplasma aurantifoliaʼ and ʻCa. Phytoplasma phoeniciumʼ were associated with almond, ʻCa. Phytoplasma phoeniciumʼ was associated with peach, ʻCa. Phytoplasma asterisʼ and ʻCa. Phytoplasma trifoliiʼ were associated with plum and ʻCa. Phytoplasma asterisʼ was associated with sweet cherry trees. Virtual RFLP analyses indicated that stone fruit phytoplasmas in East Azerbaijan are belonging to 16SrI–B, 16SrII-A, 16SrIX-C, 16SrXII-A and 16SrVI-A subgroups. This research is the first report of infection by ʻCa. Phytoplasma asterisʼ in almond and infection by ʻCa. Phytoplasma trifolliʼ in plum around the world and the first report of ʻCa. Phytoplasma aurantifoliaʼ and ʻCa. Phytoplasma trifoliiʼ presence in the northwest of Iran.